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Autoclaves quadruple gas yield from black bag municipal waste
Aerothermal Group announced today (29 October 2015) that pre-
The announcement comes on the back of new research carried out by Dr. Zhengjian Wang (Senior Research Manager) and Dr. Nigel Baily (Technical Director and Principle Engineer) at Aerothermal’s state-
As part of the research, experiments were conducted in triplicate on two waste streams. The first waste stream consisted of a sample of MSW feedstock with large items removed. Tests on this demonstrated how much extra material can go to the anaerobic digestion (AD) system as well as the increased gas yield per tonne of material fed to the AD system. The second waste stream was a sample of MSW feed stock used to demonstrate the improvements that autoclaving can achieve on a like-
The two waste samples were each divided into four portions. One portion of each waste was processed each day, four days per week. 50% of each was processed via the autoclave route and the other half was processed via a non-
After loading, the autoclave was initially evacuated using a vacuum pump to remove incondensable gases which were filtered out in activated carbon filter beds. The autoclave was then brought up to pressure and temperature (6.2 bars abs/160oC) by the injection of steam and when the temperature had equalised throughout the autoclave the load was left to “cook” for 45 minutes.
Twelve cylindrical constantly stirred tank anaerobic digesters, each of which has a working volume of 1.8 litres, were used for this trial. To start the process 1.8 litre of seed inoculums was first added into each digester. When the digesters reached the required temperatures a daily feeding, semi-
The biogas production was monitored every day and the gas composition was measured once per week. The pH of the digestate was monitored daily. A weekly composite digestate sample for each single digester was collected and the properties such as DS, VS, ammonia and VFAs were analysed once per week.
Test results on the first waste stream (where large items had been removed) revealed that autoclaving gives a gas yield of about 150m3/tonne which is more than double the target of 65m3/tonne of waste. Autoclaving also greatly increased the fraction of the waste that could be digested, as well as the gas yield from each kilogram of waste sent to the digesters which substantially reduced the amount of material requiring disposal.
Tests on the second (like-
Both waste streams showed autoclaved materials were less susceptible to the development of high VFA concentrations than un-
Christian Toll, AeroThermal’s CEO, said: “We’re very excited that our research has proved autoclaving can make black bag municipal waste disposal more efficient, cost effective and less damaging to the environment. A win-
18ft diameter autoclave moves to UTC Aerospace Prestwick
Aerothermal Group and AIC Group today (21 September) announced that they have successfully completed the move of an 18ft diameter autoclave from Scunthorpe to UTC Aerospace’s Prestwick facility.
The autoclave is so large that the move required the Highways Agency to make special arrangements for the transfer.
This is a major milestone in the contract to provide UTC with a custom-
The autoclave is the first of its size in the UK and will enable UTC Aerospace Systems’ Prestwick Scotland facility to maintain, repair and overhaul larger nacelles systems fitted to the next generation of wide-
The autoclave will be operational by the end of 2015. It will run on AIC’s Autoclave Management and Control System (AMCS) which provides significant production efficiencies and energy savings as well as aerospace compliant QA reports. The autoclave will be maintained by AIC in a 10-
Ian Toll, founding director of Aerothermal Group, said: “We have achieved a major milestone in this project and it was fantastic to see the autoclave begin its installation in UTC. We are still firmly on track to see the autoclave operational in the coming months.”
Nigel Clifford, Sales Director of AIC Group, said: “Manufacturing an autoclave requires complex engineering design skills. And moving one of 18ft diameter was also a challenge. However we have overcome these challenges and are confident that the autoclave will soon be working efficiently on large engine nacelles.”
Steve Callan, Managing Director of UTC Aerospace Systems – Aerostructures Prestwick Service Centre, said: “We are committed to maintaining the high quality capabilities and services our customers expect. This new autoclave better positions us to be a leader in the new large engine nacelle products that have begun entering the market. It further demonstrates our dedication to meeting our customers’ requirements and supporting them into the future.”
SEWAGE GENERATES ALMOST HALF MORE METHANE IF PRE-
Aerothermal Group today (7 July) announced that pre-
Three batches of dewatered sewage sludge cakes from three different sources were separately treated by autoclaving at 160⁰C (5.2 bar gauge) for 45 minutes at the company’s Poole facility. A biochemical methane potential (BMP) test was carried out on both autoclaved and un-
Stable conditions for digesters treating the autoclaved and the un-
The experiments were carried out in duplication for each tested sample. Two inoculum control digesters were also run alongside, fed with seed sludge and tap water only. The inoculums were prepared by screening (1mm mesh) out large inert and undigested substrates.
Three batches of sewage sludge cakes were collected and separately autoclaved at a temperature of 160⁰C (5.2 bar gauge) for 45 minutes. After autoclaving, the sludge masses were increased 1.3 – 1.5 times due to the addition of water (from steam condensing). Also after autoclaving, the sludge had a more homogenous slurry-
It was concluded that stable digester operation is possible at a loading rate of 5 kg VS/m³/day, and under these conditions, an autoclaving pre-
Christian Toll, AeroThermal’s CEO, said: “We are very excited that we have proven that the British designed and built, AeroThermal hydrolysis system, is an efficient way to produce a higher yield of methane gas, through autoclaving of sewage sludge cakes, to potentially be used as a source of green energy and at the same time go some way to solving the waste problem which is so damaging to our environment.”
New contract R&D facility for AeroThermal Group
AeroThermal Group, pioneers in developing innovative solutions from aerospace through to green energy from waste, announced today that its new contract R&D Facility is now open to carry out comprehensive testing in Poole, Dorset.
The laboratory specialises in the examination of the anaerobic biodegradation potential of different waste materials with or without pre-
AeroThermal has a team of specialists who use a range of high tech equipment, and are led by Dr Nigel Bailey and Dr Zhenjiang Wang. It has 36 laboratory-
• Bio Methane Potential (BMP) testing
• pH measurement
• DS & VS testing
• Biogas composition
• Ammonia Nitrogen and Total Nitrogen analysis
Dr Bailey, AeroThermal’s Technical Director, said: “Anaerobic digestion can be a key technology in solving the waste conundrum. However how to maximise the energy output while controlling by-
AeroThermal has run several hundred scientific trials on different waste streams, and its team has now written nearly 100 internal research reports. The company has already completed waste trials for a number of major waste companies and fast food restaurants.
NEW RESEARCH SHOWS THERMAL HYDROLYSIS CAN DOUBLE THROUGHPUT OF ANAEROBIC DIGESTERS AND SIGNIFICANTLY REDUCE AMMONIA CONCENTRATIONS.
New research published today by AeroThermal Group shows that pre-
This increase in performance of the digesters was maximised when the autoclave operated at a temperature of 140oC and the digesters were run at an Organic Loading Rate (ORL) of >5kgVS/m3/day.
The experiments have shown that autoclaving has the effect of producing a feedstock for AD which allows stable digestion at very high loading rates, without the addition of trace elements which could be harmful to the environment.
Stable operations have been achieved at a loading rate as high as 10 kg VS/m3/day with food waste autoclaved at 140oC, while the un-
Such significant increases in digester performance can be attributed to the denaturing of protein during the autoclaving pre-
There is a small loss in gas generation due to this denaturing of protein and the caramelisation of sugars but autoclaving at 140OC is probably the optimum temperature as only limited caramelisation will occur and any potential gas loss is more than offset by the advantages of operating stably at higher loading rates.
For the plant operator, this means that by using an autoclave, they can potentially double the throughput of the plant and in doing so, they would double revenues for only a marginal increase in operating costs, since the autoclave uses waste heat from the CHP process. This can only make for an attractive proposition to food waste AD plant operators, in a market where gate fees continue to fall.
The autoclave can easily facilitate the co-
Christian Toll, AeroThermal’s CEO, said: “In the past there has been a lot of speculation on the efficacy of pre-
“This could have a huge impact on every organisation running a digester, as fitting an autoclave into the process, a relatively straightforward process, could revolutionise the world of anaerobic digestion.”
With this ground breaking technology, AeroThermal have previously won the title of ‘Most Innovative Product and Process’ at the prestigious ADBA and Lets Recycle awards.
The AD team at AeroThermal is lead by Tony Kimber BSc (Hons), CEng, who has over 30 years experience and has been responsible for the D&B of approx 60 AD plants, successfully managing EPC contracts and leading multiple site delivery teams.
AeroThermal’s comprehensive testing facility at its laboratory and demonstrator autoclave in Poole, Dorset, is lead by Dr Nigel Bailey MA PhD and Dr Zhenjiang Wang BSc Hons PhD. They use a range of high tech equipment and provide a number of services to the industry, including the examination of waste properties and the evaluation of the anaerobic biodegradation of wastes.
AeroThermal troubleshoots digester processes, analyses plant performance and advises options for plant optimisation.
They have 36 laboratory-
The company has run several hundred scientific trials on many different types of wastes, some in conjunction with Southampton University. The AeroThermal team has now written over 100 reports and has completed waste trials for a number of major waste companies including Biffa, Shanks, Viridor, and New Earth Solutions amongst others.
This programme of experiments builds on AeroThermal’s work on the EU funded Valorgas project, in conjunction with Southampton University, where optimisation of food waste AD plant performance was explored.